Provide feedback when interacting with PR files

Issue Type: Feature Request

Hello.
This extensionis super nice, it is super useful to be able to interact with PR direcrtly from VSCode.

There is one small detail that you may not notice if you are always on a good internet connection, but it becomes noticeable on slow ones. When you interact with any file on the PR, for example you flag it as viewed, there is no feedback to tell you if something is loading, or even if you clicked the button. It will be very nice to have some visual indication.

Regards

Extension version: 0.34.1
VS Code version: Code 1.63.2 (899d46d82c4c95423fb7e10e68eba52050e30ba3, 2021-12-15T09:37:28.172Z)
OS version: Darwin x64 20.6.0
Restricted Mode: No

首先追踪 VS Code 中与 pull-request 文件相关的交互，尤其是将文件标记为已查看的操作，并检查其异步状态是如何表示的。为加载或点击状态添加可见反馈，然后验证与 PR 文件交互时，操作完成后能够提供明确的确认。